1. Field of the Invention
The present invention relates to a confocal laser scanning microscope.
2. Related Background Art
A confocal laser scanning microscope comprises a laser light source, an illumination optical system for forming a light spot by focusing a light beam emitted from the laser light source onto an object, a focusing optical system for focusing the light beam reflected by the object onto a detection surface, a detection means for detecting the light beam focused on the detection surface, and a scanning means for moving the light spot relative to the object. A laser beam is focused on an object, and optical detection is performed on the detection surface via a pinhole aperture. For this reason, the microscope has an advantage of a very small focal depth, and is used in various applications.
An arrangement for obtaining a differential interference image using such a confocal laser scanning microscope can be realized by using an arrangement of a differential interference apparatus in a conventional optical microscope. However, the arrangement becomes complicated, and requires a special objective lens with a small distortion, Nomarski prism, wavelength plate, and the like. For this reason, it is difficult to manufacture the respective optical components with required precision, resulting in an expensive apparatus.
The present inventors proposed a confocal laser scanning differential interference microscope, which can independently obtain phase information and amplitude information of an object in a compact and simple arrangement using a waveguide, in Japanese Patent Application No. 2-400212 (Japanese Laid-Open Patent Application No. 4-208913). More specifically, a laser beam is focused on an object, a double-mode channel waveguide is arranged at a spot image position of the laser spot by the focusing optical system, and a waveguide branch region for branching the waveguide into a plurality of channel waveguides is subsequently arranged. By detecting a difference between light amounts passing through the branched channel waveguides, a microscopic inclination of an object is detected.
However, the arrangement of the above-mentioned proposal can obtain a differential signal of phase information or amplitude information in the widthwise direction of the double-mode waveguide region, but has no detection capacity of a differential signal in a direction perpendicular to the widthwise direction of the double-mode waveguide region. For this reason, information in the direction perpendicular to the widthwise direction of the double-mode waveguide region can be obtained by rotating the microscope apparatus relative to an object. However, a mechanism for rotating the microscope relative to a sample is then additionally required, and a sample cannot be observed simultaneously in the widthwise direction and the direction perpendicular thereto.